ABSTRACT:Insulin is the most effective glucose-lowering agent, which stimulates glucose uptake in skeletal muscles, myocardium, and other tissues in order to control glucose homeostasis. Is is usually administered to diabetic patients through subcutaneous injection. However, the problems encountered with subcutaneous insulin injections are pain, allergic reactions, hyperinsulinemia, and insulin lipodystrophy around the injection site. Insulin if administered via the oral route will help eliminate the pain caused by injection, psychological barriers associated with multiple daily injections such as needle anxiety and possible infections. In addition, oral insulin is beneficial because it is conveyed directly to the liver, its primary site of action, via the portal circulation, a mechanism complimentary to endogenous insulin; subcutaneous insulin treatment however does not replicate the normal dynamics of endogenous insulin release, resulting in a failure to achieve a lasting glycemic control in patients. Insulin in its present form cannot be administered through oral route. Scientists have been trying hard to design an oral delivery system for insulin by applying several approaches.